Mask



FIG. 1 is a front perspective view of a mask showing my new design;

FIG. 2 is an enlarged top plan view thereof;

FIG. 3 is an enlarged side elevational view thereof showing the relative positions of a user in phantom lines;

FIG. 4 is an enlarged second side elevational view thereof, showing a user in phantom lines;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is an enlarged rear elevational view thereof;

FIG. 7 is an enlarged bottom plan view thereof; and,

FIG. 8 is a rear elevational and cross-sectional view, taken along 8--8 of FIG. 3. 

The ornamental design for a mask, as shown and described. 